The present invention relates to in-line air humidifiers and systems using such humidifiers, in particular to in-line humidifiers and systems using same in connection with medical procedures and techniques and more particularly to medical procedures and techniques involving the eye and eye surgery (e.g., retinal tear or detachment surgery).
Retinal tears can occur when the vitreous, a clear gel-like substance that fills the centers of the eye, pulls away from the retina thereby leaving behind a tear or hole in the retina. Rhegmatogenous retinal detachments can result if the retinal breaks, i.e. tears or holes in the retina of an eye are not treated. With retinal breaks, fluid from the vitreous apparently seeps through the retinal break and accumulates under the retina. The degree of detachment is measured by the volume of subretinal fluid as well as the area of the retina involved. Some symptoms of retinal detachment include the presence of floaters, flashes, shadows or blind area, decreased visual acuity and metamorphopsia
A number of techniques are employed for treating retinal detachments including using a scleral buckle, pneumatic retinopexy, cryopexy (i.e., freezing) and photocoagulation using a laser or xenon arc light source. These techniques may be used alone or in combination with each other to treat the retinal detachments for example, a combination of using a scleral buckle and photocoagulation. Additional retinal tears with little or no nearby detachment can be treated using photocoagulation or cryopexy.
In the photocoagulation technique when using a laser, the retinal break is surrounded with one or more rows of a plurality of laser burns or laser heat spots. These laser heat spots or bums produce scars, which prevents fluid from passing through and collecting under the retina. In the photocoagulation procedure, a gas is exchanged for the vitreous fluid being aspirated from within the eye so the gas is intraocular when performing photocoagulation. Typically, the gas is air from a tank that may be filtered and sterilized before it is infused into the eye.
Such air infusion of into the eye, however, can be quite problematic. For example, the infused air often can cause the lens of a patient""s eye to become cloudy and dry, complicating the surgical procedure and creating conditions that can result in injury to the patient.
It thus would be desirable to have improved devices, systems and methods for infusing a gas, particularly air, to a patient""s eye during eye surgery procedures. It would be particularly desirable to have improved devices, systems and methods for infusing air or other gas to a patient""s eye during surgery wherein the eye lens remains substantially clear and moist.
We have now produced new devices and methods that enable infusing air or other gases into a patient""s eye during surgical procedures whereby the eye remains quite clear and moist.
More particularly, the present invention provides a humidifier device and a system using such a humidifier, in particular a system configured for use in eye surgery, such as retinal tear and/or detachment surgery. The invention also provides related methods for humidifying air and infusing air during eye surgical procedures as well as a method for treating a retinal tear or detachment.
The methods of the invention in generally comprise providing a humidifier device, humidifying (i.e. adding moisture) to gas via the device and infusing the humidified gas to a patient""s eye typically during an eye surgery procedure. The humidifier device is typically in-line, i.e. positioned in a gas flow path between the gas source and the patient""s eye.
Preferred humidifier devices of the invention generally include a housing and a humidifying section disposed within the housing. The housing comprises an inlet and an outlet connection or port that fluidly communicates with the interior of the housing. The humidifying section is located within the housing so air entering the housing via the inlet connection passes through the humidifying section and thence out through the outlet connection, thereby humidifying the flowing air.
The humidifying section preferably includes material (preferably hydroscopic) that can be hydrated (e.g., initial charged with a liquid, such as a sterile saline solution) and selectively release moisture to the gas as it passes through the humidifying section. Preferably, the material also is a bacteriostatic material. Alternatively, the humidifying section is treated with a germicide or other agent. In general aspects, the humidifying section is any type of reservoir that allows for efficient humidification of the gas flowing therethrough. Also, in general aspects the hydroscopic material includes any one of a number of materials known in the art, including but not limited to cellulose, absorbent synthetic materials, papers including corrugated paper, and the like. Additionally, the humidifying section can have a variety of structural configurations and shapes including a cylinder that permits the passage of air between the inlet and outlet connections. In a particular embodiment, the humidifying section is a cylinder of concentric layers of corrugated paper or other absorbent material configured to maintain a desired shape and integrity of the air flow passage after the corrugated absorbent material has absorbed a desired quantity of liquid. Such a preferred cylinder design is suitably configured to allow the air to flow along the long axis of the cylindrical humidifying section.
The device housing may be suitably constructed of any one of a number of materials known in the art that is appropriate for the intended use including maintaining structural integrity while being exposed to the humidified air. More particularly, the housing is constructed of a plastic material such as a rigid polypropylene, polyethylene and the like. In a preferred embodiment, the housing includes a visual port or is constructed, at least in part, of a clear plastic material that allows a surgeon or other device user to observe the condition of the hydroscopic material of the humidifying section within the housing.
In one aspect of the invention, the device housing is constructed to form a one-piece structure in which is disposed the humidifying section. In another aspect of the invention the housing is constructed so as to have two or more members that are releasably secured to each so a single structure is formed when the humidifier is assembled for use.
A humidifying system of a device of the invention suitably will be in communication with a source of flowing gas (particularly air) and an in-line humidifier as described above. Such a system can further include an air filter that filters the air before it passes through the humidifier. In a more specific embodiment, the filter or system further includes the capability to sterilize the air. The system typically includes tubing that interconnects the various components that form the system. The source of air that flows through the system and is infused into a patient""s eye suitably can be a commercially available pressurized tank of air or the like.
Other aspects and embodiments of the invention are discussed below.